Air supply means for diesel engines



July 8, 1941. H. MARUHN AIR SUPPLY MEANS FOR DIESEL ENGINES Filed Feb.24, 1939 INVENTOR /%=rAe,/V m// BY I ATTORNEY Patented July 8, 1941 AIRSUPPLY MEANS FOR DIESEL ENGINES Herbert Maruhn, Stuttgart-Bad Cannstatt,Germany, assignor to Daimler-Benz Aktiengesellschaft,Stuttgart-Unterturkheim, Germany Application. February 24, 1939, SerialNo. 258,211 In Germany February 26, 1938 Claims.

The invention relates to Diesel. engines or other air-inducing orair-compressing internal combustion engines, particularly for motorvehicles; An important object is to provide means for-increasing thetemperature of the air which influences engine cooling, for example, airlocated under the engine bonnet, and an independent air intake for theadmission to the engine of cold combustion air.

The Diesel engine is'particularly sensitive to excessive cooling and itstemperature condition ought not to pass below a certain lower limit.High cooling water temperatures are desirable for the engine output andfor readiness in start- By the use of a radiator shutter or acorresponding control device, the air under the engine bonnet and alsothe radiator may be kept sufficiently warm, so that the radiator acts asa heat accumulator. Such an arrangement is particularly advantageous inwinter and is essential for quick re-starting of the engine with a coldoutside temperature.

0n the other hand, if air at comparatively high temperature is drawn inby the engine, the charging and therewith the output of the enginebecome less than if air at lower temperature is drawn in. However,whereas there is the danger with carburetter engines that the formationof:

the mixture is impaired if the air drawn in falls rubber cushions c andd which permit the engine to swing about a longitudinal axis C-D'passing approximately through thecentre of gravity. Arranged in front ofthe engine is the radiator e to which the cooling water warmed in theengine flows through the passage I. From the radiator e the coolingwater flows through -the passage g to a pump h driven by the engine,-

which pump delivers the cooling water back through the pipe-connections5 to the coolingwater space of the engine and thus maintains itconstantly in circulation. The passages and g resiliently in knownmanner so that the engine below a certain temperature and consequentdissociation of the mixture or condensation ofthe fuel is to be feared,it is possible with Diesel engines to supply as cold air as possible tothe engine with particular advantage, since this engine draws in andcompresses air only. For this reason, the invention provides incombination, a radiator shutter or control and a combustion air intakedisposed outside of the engine space or outside of the radiator shutterso that the thermal condition of the admitted combustion air remainsunaffected by the closing of the radiator shutter and the enginereceives combustion air of as low a temperature as possible. IPreferably, the entry of the air into the engine inlet passage takesplace at a point of comparatively high external air pressure,particularly at the front end of the vehicle in front of the radiator.The charging and the output of the engine may be further improved bythis means.

One embodiment of the invention by way of example, is illustrateddiagrammatically in th annexed drawing.

In the drawing, the Diesel engine b is mounted on the frame a, forexample by means of .the

can swing about the axis C-D.

The engine is arranged under the bonnet'i. Preferably the engine spaceis also closed below by a bottom plate is. Disposed in front of theradiator is the radiator protecting grid Z and between the two there isaradiator shutter of the louvre type formed by adjustable flaps m. Theflaps are eachniounted rotatably about shafts n which runhorlzontally inthedrawingbut in practice will generally run vertically. The

individual fiaps'are connected together by a rod 0 and are adjustabletogether by a two armed lever arm 12 which can be actuated from thedrivers seat by a rod q, for example a rod adjustable lengthwise by theaid of a ratchet device r and handle s. p

The combustion air for the engine is taken in at the front end of. theradiator by a funnel t and is conducted through the upper part of theradiator space and by way of a flexible passage 10 to the air filter uwhence the air passes into the suction pipe 11) of the engine. The fuelis supplied by the, fuel pump a: to the injection nozzles 1 in a mannerknown per se, it being possible, for example, for the fuel to beinjected into pre-combustion chambers.

By adjustably opening or closing the flaps m of the radiator shutter,the temperature under-J I neath the engine bonnet can be maintained at adesired favourable value without the temperature of the inducedcombustion air being practically influenced thereby. Even with theshutter closed and with a high temperature inside the engine space, coldcombustion air and consequently a high weight of air are drawn in.Experiments have shown that the weight of air then drawn in isapproximately 5-15% greater than when the air is drawn in fromunderneath the engine bonnet. The output of the engine is increased alsoin similar fashion.

Particularly advantageous in combination with the provision of theradiator shutter is the provision of adjustable flaps in the side wallsof the engine space, these flaps being preferably adjusted at the sametime as the radiator shutter by a common actuating linkage. This iseffected in simple fashion by jointing a connecting rod 8 to the one armof the two-armed lever p adjustable by the rod q, the rod 8 beingengaged with the flaps 1. A particularly precise control of the quantityof air flowing through the engine space can thus be achieved, anddisadvantageous loss of heat from the engine or cooling water can beavoided in an especially effective fashion.

Furthermore, in combination with the radiator shutter, the cooling waterheated by the closure thereof may be utilised for heating the interiorspace of the vehicle. The heated air underneath the engine bonnet mayalso serve the same purpose, the air being, for example, caught by afunnel after its passage through the radiator and conducted to theinterior space of the vehicle.

It is advantageous to bring the suction opening t for the combustion airas near as is permitted by the constructional arrangement to the axis ofswinging C--D of the engine, so that the passage 11. experiences assmall relative movements as possible at the points of connection. Forexample, the suction passage t, u for the combustion air may also hecarried directly through the radiator and the radiator shutter.Moreover, it may'also be connected rigidly to the engine and partake inits swinging movements.

In some cases, the inlet opening to the suction passage for thecombustion air may also be disposed at some point other than the frontend or the vehicle, but it is advantageous to provide the inlet openingat a point of comparatively high external-air pressure. Thus, with theconstructional example illustrated in the drawing,

the dynamic pressure arising at the front end will produce a certainadditional charging of the engine or reduce the loss of output caused bythe I claim:

1. In a vehicle driven by an engine of the compression-ignition type,means forming an engine compartment at the front of the vehicle,including a hood and a radiator grill provided with a plurality oi!vrelatively narrow apertures and one relatively large opening, anadjustable louver positioned immediately behind the narrow apertures ofsaid grill without obstructing said large opening, a radiator positionedimmediately behind said louver, conduits for supplying cooling water toand from said radiator, from and to said engine, a funnel having itsmouth surrounding said opening and its tube extending rearwardly, meansfor connecting said tube for supplyin combustion air to said engine,means for introducing fuel into said engine independently of saidcombustion air, and means for adjusting said louvers, whereby thetemperature about said engine in said engine space may be raised to apredetermined height, while relatively cold air will be suppliedinteriorly of said engine, independently of the temperature within saidengine space.

2. The combination according to claim 1, wherein said opening ispositioned at a point of relatively high external air pressure resultingfrom movement of the vehicle.

3. The combination according to claim 1, in combination with exitshutters along the sides of said engine space, and means for controllingsaid shutters simultaneously with said louvers.

4. In a vehicle driven by an engine of the compression-ignition type,means forming an engine compartment at the front of the vehicle,including a hood having air inlet openings and air outletopeningsjadjustable means for throttling and closing theair inletopening in order to raise the temperature about said engine in saidcompartment, anair inlet conduit for an! plying combustion air to saideng e. independently, of said adjustable means for throttling andclosing the air. inlet opening; said conduit having a separate" airinlet opening outside of said engine compartment, thereby supplyingrelatively cold air interiorly of the engine independently of thetemperature within said space and preventing air from entering theinteriorof the engine out of said engine compartment, and means forintroducing fuel into said engine independently a of said combustionair.

5. In a vehicle, the combination'acoording to claim 4, in combination.with adjustable means for closing the air outlet opening so as toprevent my invention 8 d f ned in the cl ms which air from flowing outof said engine compartment.

follow.

HERBERT MARUW.

